The purpose of this study was to test the phase-shifting and entraining effects of melatonin in human subjects. Five totally blind men were found in a previous study to have free-running endogenous melatonin rhythms. Their rhythms were remarkably stable, so that any deviation from the predicted phase was readily detectable. After determination of their free-running period and phase, they were given exogenous melatonin (5 mg) at bedtime (2200 hr) for 3 weeks, in a double-blind, placebo-controlled trial. The effects on the endogenous melatonin rhythm were assessed at intervals ranging from several days to 2 weeks. Exogenous administration of melatonin phase-advanced their endogenous melatonin rhythms. In three of the subjects, cortisol was shown to be phase-shifted in tandem with the melatonin rhythm. A sixth subject [one of the coauthors (JS)] was previously found to have free-running cortisol and temperature rhythms and was plagued by recurrent insomnia and daytime sleepiness. He had tried unsuccessfully to entrain his rhythms for over 10 years. After he took melatonin (7 mg at 2100 hr), his insomnia and sleepiness resolved. Determination of his endogenous melatonin rhythm after about a year of treatment demonstrated endogenous rhythms that appeared normally entrained. The treatment of blind people with free-running rhythms has many advantages for demonstrating chronobiological effects of hormones or drugs.

Preterm babies are exposed to multiple stressors and this may have long-term effects. In particular, high levels of endogenous cortisol might have a programming effect on the hypothalamicpituitary-adrenal axis as may administered glucocorticoids. In this study, we aimed to test the hypothesis that the level of endogenous and exogenous glucocorticoid exposure during the neonatal period predicts the saliva cortisol response to immunization at 4 mo of age. We followed 45 babies born below 32 wk gestation. We showed that their concentration of plasma cortisol during the first 4 wk was 358, 314, 231, and 195 nmol/L cortisol, respectively (geometric mean). This is four to seven times higher than fetal levels at the same gestational age range. We used routine immunization at 4 mo and 12 mo as a stressor and measured the change in saliva cortisol as the stress response. Mean circulating cortisol in the first 4 wk predicted the cortisol response at 4 but not at 12 mo. Path analysis showed that birthweight for gestational age, therapeutic antenatal steroids, and therapeutic postnatal steroids also contributed to the magnitude of the saliva cortisol response at 4 mo. There is considerable evidence from animal experiments that early exposure to stress, either in the antenatal or in the immediate postnatal periods, can have long term effects on both the function of the HPA axis, and on behavior (1-5). In general, the HPA axis of the offspring becomes hyperresponsive to a novel stressor. These effects are mediated, at least in part, by activation of the maternal HPA axis and the effect of fetal cortisol or corticosterone (in rodents) on the developing brain. These effects can, in some paradigms, be mimicked by synthetic glucocorticoids (6 -8). Until recently, this has been little studied in humans. It does appear that cortisol from the mother crosses the placenta in sufficient amounts to affect the fetus (9,10), although there is so far no direct evidence that maternal cortisol alters infant development. However, there is increasing evidence from epidemiologic studies that maternal stress and anxiety during pregnancy has an adverse effect on the development of the fetus and on the later behavior and cognitive development of the child (11-16).Preterm babies are exposed both to a stressful environment, with concomitant endogenous glucocorticoid release, and may also be exposed, antenatally and postnatally, to exogenous glucocorticoids used therapeutically. If the animal models are relevant, one would predict that these infants would show long-term effects, both in HPA axis response and in behavior. Babies born extremely preterm are at risk of later behavioral problems, most noticeably with attention deficit disorders (17). Recent evidence suggests that antenatal glucocorticoid exposure has long-term effects on brain development (18). Davis et al. (19) have shown preterm babies exposed to antenatal betamethasone had a lower saliva cortisol response to a heel stick than matched controls at 3-6 d after delivery. ABSTRACT1233 c...

The objectives were to evaluate the effect of synchronization protocols on follicular development and estradiol 17-beta (E(2)) and progesterone (P(4)) concentrations in dairy heifers. In experiment 1, 36 heifers were assigned to 1 of 6 synchronization protocols in a 3 x 2 factorial design: presynchronization with GnRH on study d -6 or -9 [study d 0 = initiation of the Cosynch + CIDR (controlled internal drug releasing insert containing P(4)) protocol] or no presynchronization (control) and one injection of PGF(2 alpha) or not on study d 0. In experiment 2, 126 heifers were assigned to 1 of 4 synchronization protocols in a 2 x 2 factorial arrangement: presynchronization or not with GnRH on study d -6 and injection of PGF(2 alpha) or not on study d 0. In experiments 1 and 2, all heifers received a modified Cosynch protocol with CIDR for 7 d starting on study d 0. After the PGF(2 alpha) of the Cosynch and removal of the CIDR, heifers were detected in estrus and inseminated. Those not inseminated by study d 10 received an injection of GnRH and were timed-inseminated. Ovaries were scanned by ultrasound on d 0, 2, and 5, daily from d 7 to 14, and on d 16. Blood samples collected on d 0, 2, 7, 9, and 16 were analyzed for P(4), and the blood sample collected on d 9 was analyzed for E(2). Pregnancy was diagnosed at 28 and 40 +/- 3 d after artificial insemination. In experiment 1, there was a tendency for the presynchronization protocol to affect the proportion of heifers ovulating in response to the first GnRH injection of the Cosynch + CIDR protocol. In experiment 2, a greater proportion of presynchronized heifers ovulated in response to the first GnRH injection. Although heifers receiving PGF(2 alpha) had larger ovulatory follicles on d 7 and before ovulation and shorter intervals to estrus and ovulation, these heifers tended to have decreased concentrations of E(2) during proestrus. Presynchronization of dairy heifers with GnRH increased ovulation in response to the first GnRH injection, and treatment of heifers with PGF(2 alpha) at initiation of the Cosynch + CIDR protocol increased the size of the ovulatory follicle and reduced the intervals to estrus and ovulation.

The objectives of this study were to evaluate the effect of reproductive protocols and reproductive tract score on reproductive performance of dairy heifers and economic outcomes of breeding programs. Holstein heifers (n = 534), 13 +/- 1 mo of age, were randomly assigned to 1 of 4 reproductive protocols. On the day of enrollment (d 0), heifers were palpated per rectum and received a score according to the maturity of their reproductive tract (1 = prepubertal; 2 = peripubertal; and 3 = puber-tal). Estrous detection-control heifers (CON, n = 146) received no treatment and were inseminated on detection of estrus for 28 d. Prostaglandin F(2alpha)-treated heifers (PGED, n = 137) received 1 injection of PGF(2alpha) on d 0 and were inseminated on detection of estrus; heifers not in-seminated by d 14 received a second injection of PGF(2alpha) and were observed for estrus and artificial insemination (AI) for an additional 14 d. Heifers enrolled in the estrous detection-timed AI (EDTAI, n = 140) treatment received a controlled internal drug-release (CIDR) insert on d 0, and 7 d later, the CIDR was removed and all heifers received an injection of PGF(2alpha), heifers received AI on detection of estrus, and those not inseminated by 72 h after PGF(2alpha) received an injection of GnRH concurrent with AI. Heifers in the GnRH-timed AI (GTAI, n = 111) treatment received 1 injection of GnRH on d 0, on d 6 heifers received a CIDR insert and injections of GnRH and PGF(2alpha), on d 13 the CIDR was removed and heifers received an injection of PGF(2alpha), and 48 h later all heifers received an injection of GnRH and AI. Pregnancy was diagnosed at 32 +/- 3 and 62 +/- 3 d after AI. Cost of reproductive protocols and their economic outcomes were calculated for a 28 d period beginning at enrollment. Heifers in the PGED treatment were inseminated at a faster rate than CON heifers. A smaller proportion of prepubertal and peripubertal heifers were inseminated within 14 d of enrollment compared with pubertal heifers. Pregnancy per AI of CON and PGED heifers was greater compared with EDTAI and GTAI heifers. Proportion of GTAI heifers pregnant at the end of the 28-d breeding program was or tended to be smaller compared with PGED and CON heifers, respectively. Heifers in the CON and PGED treatments had the smallest cost per pregnancy followed by heifers in the EDTAI and GTAI treatments, respectively. When different scenarios were evaluated, however, the mean cost per pregnancy was smallest for PGED heifers. Cost per pregnancy generated was greatest for prepubertal heifers, whereas pubertal heifers had the smallest cost per pregnancy generated. Treatment of dairy heifers with PGF(2alpha) every 14 d until insemination and pregnancy results in the best economic outcomes, and screening heifers according to RTS may prove beneficial to identify heifers that may not be pubertal and would have compromised reproductive and economic performance in a breeding program.