Parathyroid function in uremic children during periods of renal insufficiency, hemodialysis, and transplantation.

Function of the parathyroid gland was evaluated in children with renal insufficiency prior to and after imitation of hemodialysis, and again following renal transplantation. Serum levels of immunoreactive parathyroid hormone responded appropriately to increases or decreases of serum calcium concentrations in the three groups. Functional and histologic studies in the children with renal insufficiency demonstrated the cause of their elevated circulating levels of iPTH to be diffuse parathyroid hyperplasia.

Renal wastage of insulin in children with diabetes mellitus.

In normal human beings the percentage of serum insulin excreted in the urine is constant over a wide range of values. The quantity of immunoreactive insulin found in the urine is believed to reflect the level of free insulin in the serum. Immunoreactive insulin was measured in the urine of nondiabetic children and diabetic children receiving exogenous insulin.

The response of pituitary gonadotropes to a constant infusion of luteinizing hormone-releasing hormone (LHRH) in normal prepubertal and pubertal children and in children with abnormalities of sexual development.

The pattern of LHRH-evoked release of LH and FSH by pituitary gonadotrophs and the concomitant gonadal steroid secretion were studied in 28 pubertal and 16 prepubertal children. LHRH was administered at doses of 100 mug and 10 mug by a constant-infusion pump over 3 hours following a 2-hour control period. Gonadotropin concentrations were measured at 15-minutes intervals.

Evaluation and management of the child with delayed pubertal development.

The physical and hormonal changes of puberty are presented and the wide range of ages at which the pubertal process may begin is emphasized. The great variability in the timing of onset of adolescence, its rate of progression, and the age of completion are detailed. The causes of delayed adolescence in males and females are considered.

Effects of new multi-site hormone blockers on the fertility of male rats.

The effects on the fertility of adult male rats of six new synthetic steroids: I, 3-cyano-5alpha-androst-1-en-17-one; II, the 17beta-acetate form of I; III, 17beta-hydroxy-5beta-cyano-androstan-3-one; IV, 6-methylpregnenolone; V, 17beta-hydroxy-17alpha-ethynyl-5beta-cyano-19-norandrostan-3-one; and VI, 19-norspiroxenone (oestr-4-en-3-one-spiro-17alpha-2'-[tetrahydrofuran]) have been tested. After 6 weeks of treatment with daily doses of 5 mg (I, II, III), 15 mg (IV) or 10 mg (V, VI) only steroid VI blocked the completion of spermatogenesis and reduced the number of foetuses sired in at least five females/male. Steroid VI also diminished seminal vesicular, prostatic, testicular and epididymal weights.

Recent advances in calcium metabolism. II. Disorders of calcium homeostasis.

Abnormalities of calcium and mineral metabolism are described in relation to the differential diagnosis, clinical characteristics, diagnostic procedures, and treatment of infants and children with hypocalcemia, hypercalcemia, rickets, chronic renal insufficiency, and other disorders of calcium metabolism. Understanding of the basic pathogenesis of each abnormality of calcium homeostasis is essential for the rational management of affected patients.

Growth hormone and prolactin in the fetus.

Growth hormone is released from pituitary glands maintained in tissue culture as early as 5 weeks after conception. It has been identified in the fetal anterior pituitary gland by immunologic and biologic techniques between 7 and 15 weeks of gestation. Immunoreactive pituitary GH levels increase rapidly between 10 and 14 weeks of gestation to maximal levels at 30-34 weeks.

Recent advances in calcium metabolism. I. Mechanisms of calcium homeostasis.

Within recent years newly acquired knowledge has provided a clearer understanding of some aspects of the complex mechanisms that collectively maintain calcium homeostasis within body fluids and it is our intent to define current concepts of the interrelationship of these various factors to the end that fuller understanding may be available concerning the maintenance of calcuim homeostasis in health as well as features which result in its disruption and the consequent effects of imbalances of calcium in various disease states. In this first section dealing with the physiologic state, there are included descriptions of: (1) the metabolism of vitamin D, the synthesis of its active metabolites, 25 OHD3 and1.25(OH)2D3, and the metabolic actions of the active vitamin D metabolite and analogues upon gastrointestinal, bone, and kidney functions; (2) the synthesis, secretion, and metabolic activity of parathyroid hormone and the difficulties with the radioimmunoassay of PTH related to the number of PTH-like peptides in the circulation; and (3) the chemistry, metabolism, and biologic activities of calcitonin, a hypocalcemic principle derived from the parafollicular cells of the thyroid gland.

Effect of short-term castration and starvation upon hypothalamic content of luteinizing hormone-releasing hormone in adult male rats.

A sensitive and specific radioimmunoassay for hypothalamic LH-RH has been described. Within 7 days after castration there is a significant decline in hypothalamic content of LH-RH in adult male rats. Total starvation for 7 days does not affect hypothalamic content of LH-RH in either intact or castrated rats.

Hormonal changes of adolescence.

Pubescence is characterized by many physical, emotional, and hormonal changes. The hypothalamic-pituitary-gonadal system is maintained in a dormant state (with a low level of activity) during prepubertal years by higher central nervous system inhibition. With the onset of adolescence, the reproductive endocrine system becomes increasingly active.

Effect of synthetic luteinizing hormone--releasing hormone in newborn rats.

Administration of synthetic LH-RH to male and female rats on the first day of life reduced pituitary content of FSH and LH and increased serum concentrations of LH.

Pituitary hormone secretion in the genectically male rat pseudohermaphrodite.

Pituitary content or concentration of follicle-stimulating hormone (FSH), prolactin and growth hormone in the genetically androgen insensitive male rat pseudohermaphrodite is intermediate between normal male and female rats, while pituitary luteinizing hormone (LH) concentration and serum FSH levels are the same as in the normal male. The concentration of serum LH, prolactin and growth hormone indicated no sexual dimorphism. Although the pseudohermaphrodite is genetically male with a female phenotype, our results suggest some degree of masculinization of the hypothalamic-pituitary system.