Breed differences in circulating equine relaxin.

Equine relaxin has been previously determined in a small number of pregnant Thoroughbred mares. To better define the normal pregnancy pattern of relaxin, the current study reports on a much larger number of mares. It also was designed to determine if all equids have the same gestational pattern of relaxin secretion.

Relationship of serum estradiol and progesterone concentrations to the excretion profiles of their major urinary metabolites as measured by enzyme immunoassay and radioimmunoassay.

Paired daily blood and urine samples were collected from 10 apparently healthy premenopausal women to compare the hormone profiles of estradiol (E2) and progesterone in serum with those of estrone conjugates (E1Conj) and pregnanediol-3-glucuronide (PdG) in urine. Serum hormones were measured by radioimmunoassay (RIA) kits, whereas the urinary steroid metabolites were assessed by both RIA and enzyme immunoassay (EIA). RIA and EIA values for urinary E1Conj and PdG were not different, and both methods produced urinary profiles that paralleled the profile of the parent steroid in serum.

Determination of the source of immunoreactive relaxin in the cat.

We have recently reported the secretory profile of relaxin throughout gestation in the cat. Because the appearance of relaxin begins at about Day 20 (Day O = ovulation) and because implantation begins shortly before this at Days 13-14, we hypothesized that relaxin was of feto-placental origin. To test this hypothesis, we used 4 experimental groups: 1) Control (laparotomy-only at Day 23 or 42, n = 4); 2) Early Ovariectomy (Ovx, bilateral ovariectomy between Days 23 and 26, n = 4); 3) Late Ovx (bilateral ovariectomy between Days 40 and 44, n = 4); 4) Tissue Removal (removal of feto-placental units, uterus, and one ovary on Days 16, 21, 28 and 35, n = 1 per day).

The effect of different photoperiods on plasma concentrations of melatonin, prolactin, and cortisol in the domestic cat.

These studies investigated the effects of photoperiod on plasma melatonin, PRL, and cortisol concentrations in cats. Animals were placed in one of three different photoperiod regimens [short (SP), 8 h of light, 16 h of darkness (8L:16D); normal (NP), 14L:10D; long (LP), 24L:OD] 140 days before experimentation (n = 4/group). In the first experiment, melatonin, PRL, and cortisol concentrations were measured in plasma obtained at 2-h intervals for 24 h.

Comparison of aqueous porcine ACTH with synthetic ACTH in adrenal stimulation tests of the female dog.

The adrenocortical (plasma corticosteroid) responses in female dogs given porcine ACTH in gelatin (1-39 amino acid sequence) and synthetic ACTH (1-24 amino acid sequence) were compared. Sixteen dogs were used. Each dog underwent 4 different ACTH stimulation studies, these being done with a 4- to 8-week interval.