Distribution of arginine-vasopressin and vasoactive intestinal peptide messenger RNA in the suprachiasmatic nucleus of the sheep.

The distribution of mRNAs for vasoactive intestinal peptide (VIP) and arginine-vasopressin (VP) was studied in the hypothalamus of the sheep by in situ hybridization. VIP mRNA was detected in the supraoptic nucleus (SON) and in the median part of the suprachiasmatic nucleus (SCN). VP mRNA was observed in the magnocellular system of the hypothalamus and in the dorso-lateral part of the SCN.

Bilateral lesions of the suprachiasmatic nuclei alter the nocturnal melatonin secretion in sheep.

The hypothalamic suprachiasmatic nuclei (SCN) constitute both the biological clock of many circadian rhythms, and the first relay in the transmission of light cues from the retina to the pineal gland, which releases, via nocturnal melatonin secretion, an endocrine expression of the daylength. The aim of the present work was to investigate the precise role of the SCN in the entrainment of the nocturnal rhythm of melatonin (MEL) in sheep. Bilateral lesions of the SCN were performed via a transsinusal surgical approach in 10 adult rams submitted to a constant photoperiod (16:8D).

The suprachiasmatic nucleus in the sheep: retinal projections and cytoarchitectural organization.

The retinal innervation, cytoarchitectural, and immunohistochemical organization of the suprachiasmatic nucleus (SCN) was studied in the domestic sheep. The SCN is a large elongated nucleus extending rostrocaudally for roughly 3 mm in the hypothalamus. The morphology is unusual in that the rostral part of the nucleus extends out of the main mass of the hypothalamus onto the dorsal aspect of the optic chiasm.

A new surgical approach to the ram suprachiasmatic nuclei.

In mammals, lesions of the suprachiasmatic nuclei (SCN) cause alterations in several biological rhythms. Investigation of the role of the ovine SCN requires complete bilateral lesions of the nuclei. However, the elongated shape, location and horizontal orientation of this hypothalamic structure prohibit a classical stereotaxic vertical approach.

Effect of an acute exposure of rat testes to gamma rays on germ cells and on Sertoli and Leydig cell functions.

Germ cells and Sertoli and Leydig cell functions were studied from 7 to 180 days after an acute exposure of 2-month-old rat testes to 9 Gy of gamma rays. Body weight, testis and epididymal weights were recorded. Sertoli cell parameters (androgen-binding protein, ABP, in caput epididymis and plasma follicle stimulating hormone, FSH) and Leydig cell parameters (plasma luteinizing hormone, LH, testosterone and prostate and seminal vesicle weights) were determined together with the number of germ cells and Sertoli cells.

Relaxin-like peptide in ascidians. II. Bioassay and immunolocalization with anti-porcine relaxin in three species.

A substance related to vertebrate relaxin, previously identified by radioimmunoassay and Northern hybridization in the ascidian Herdmania momus, was also purified and tested in bioassay in another species, Ciona intestinalis. In addition, immunocytochemistry with anti-porcine relaxin was performed, at the light and electron microscopic levels, on sections of ovary from three different species, living in various environmental conditions. A positive immunoreaction was located specifically in follicle cells surrounding mature oocytes.

Influence of germ cells upon Sertoli cells during continuous low-dose rate gamma-irradiation of adult rats.

The effects of continuous gamma-irradiation of adult rats at two low-dose rates (7 cGy and 12 cGy/day; up to a total dose of 9.1 Gy and 10.69 Gy 60Co gamma-ray, respectively) were investigated.

Testicular growth and hormonal parameters in the male Snell dwarf mouse.

Dwarf mice show delayed testicular growth and their adult testis weights are half the normal value. The aims of the present work were firstly, to compare the developmental profiles of plasma gonadotropins and of testicular cell multiplication and differentiation in dwarf vs normal mice and secondly, to determine the effect of hMG supplementation on dwarf mice. In the dwarf mice no pubertal rise in plasma FSH was observed, and the adult values remained very low when compared with those of normal mice; plasma LH decreased after 40 days of age and remained equal to half the normal values.

Endocrinological and histological changes induced by continuous low dose gamma-irradiation of the rat testis.

Young adult Sprague-Dawley rats were continuously whole-body irradiated with gamma rays at a dose-rate of 7 cGy/day for 92 days. Plasma LH, FSH and testosterone concentrations and testicular histology were quantified at different times during exposure. Irradiation selectively decreased spermatogonial numbers until 17 days of irradiation, following which a maturation depletion was observed.

Effects of flutamide or of supplementation with testosterone in prepubertal male rats prenatally treated with busulfan.

Male rats treated prenatally with busulfan in order to render them aspermatogenic were treated between 23 and 38 days of age either with testosterone, or flutamide. In such aspermatogenic rats, testosterone supplementation stimulated the growth of accessory sex organs, markedly decreased the secretion of gonadotrophins (by 61% for LH and 83% for FSH), decreased testicular weight (-60%) as well as all parameters relating to testicular histology. Flutamide treatment decreased the weight of accessory sex organs, stimulated the secretion of both LH (+200%) and FSH (+63%) by inhibition of the negative feedback of testosterone; endogenous testosterone secretion was increased by 363%.

Changes in testicular fluid production and plasma hormones in the adult rat after testicular 60Co irradiation.

Adult Wistar rats exposed to testicular radiocobalt irradiation (0.8 Gy) were alloted to four groups: sham control, protected control, unilaterally irradiated and bilaterally irradiated. The rats of each group were killed 30, 45, 60, 75 and 105 days after gamma-ray exposure and/or general anaesthesia.

FSH, LH and prolactin levels, ovarian follicular development and ovarian responsiveness to FSH in the Snell dwarf mouse.

The homozygous Snell dwarf mouse is sterile. It has been shown that pituitary hormone levels are low in 3 month old animals except for FSH and LH whose pituitary contents and plasma concentrations are normal. In this study, the pituitary FSH, LH and prolactin (Prl) content, the FSH plasma concentration and the ovarian follicular development of the Snell dwarf mouse were studied at 18, 20, 24, 40 and 80 days of age.

Effect of prenatal treatment with busulfan on the hypothalamo-pituitary axis, genital tract and testicular histology of prepubertal male rats.

Female Wistar rats were treated with busulfan or with solvent on Day 20 of pregnancy. Thirty male offspring of each group were killed at 38 days of age. In busulfan-treated rats, compared to controls, hypothalamic LH-RH content was decreased by 52%, whereas pituitary LH and FSH concentrations were increased by 60 and 43% respectively.

Endocrinological and histological changes induced by flutamide treatment on the hypothalamo-hypophyseal testicular axis of the adult male rat and their incidences on fertility.

Adult male Wistar rats were treated with flutamide from 90 to 105 days of age. In a first experiment, testis and accessory sex organs were weighed. In the same animals, hypothalamic LRH content, pituitary gonadotrophin concentrations, plasma LH, FSH, prolactin and testosterone levels, and testicular gonadotrophin receptors were evaluated.

Effects of supplementation with impuberal or adult testicular protein extracts on genital tract and testicular histology as well as hormonal levels in adult busulfan treated rats.

24 adult Wistar rats received one SC injection of busulfan (10 mg/kg BW) on day 0. They were injected daily from day 1 to day 10 either with BSA (1 and 2 mg/rat, n = 5 respectively), with acetonic extract of adult ram testicular cytosol (2 mg/rat, n = 10) or with acetonic extract of impuberal calf testicular cytosol (2 mg/rat, n = 4). 10 animals served as control.