Levels of maternal serum corticotropin-releasing hormone (CRH) at midpregnancy in relation to maternal characteristics.

Background: Corticotropin-releasing hormone (CRH) in maternal blood originates primarily from gestational tissues and elevated levels in midpregnancy have been linked to adverse pregnancy outcomes. Investigators have hypothesized that high levels of maternal stress might lead to elevated CRH levels in pregnancy. Yet a few studies have measured maternal CRH levels among subgroups of women who experience disproportionate socioeconomic disadvantage, such as African-American and Hispanic women, and found that these groups have lower CRH levels in pregnancy.

Dose-related actions of GnRH II analog in the cycling rhesus monkey.

Introduction: Gonadotropin-releasing hormone (GnRH) II expression, specific high-affinity receptors for GnRH II and its potent bioactivity in human and baboon tissues led us to hypothesize that GnRH II is a bioactive peptide in primates. We recently demonstrated the contraceptive activity of GnRH II analog in rhesus monkeys. In the present experiment, we extended those studies to the dose-related action of this analog on parameters of luteal function and conception.

Primary amenorrhea associated with ovarian leiomyoma in a baboon (Papio hamadryas).

A 6-y-old female baboon was examined due to absence of menstrual cycling and secondary sex characteristics and failure to reproduce. The mammary glands and vaginal introitus were hypoplastic, the clitoris was prominent, and the perineal skin was immature with lack of cyclic color alterations and sexual swelling. Evaluation of the reproductive tract revealed a hypoplastic uterus and rudimentary ovaries with the presence of an ovarian leiomyoma within the right ovary.

Effect of ductus ligation on cardiopulmonary function in premature baboons.

Rationale: The role of the patent ductus arteriosus in the development of chronic lung disease in surfactant-treated premature newborns remains unclear.

Objective: To examine the effects of ductus ligation on cardiopulmonary function and lung histopathology in premature primates.

Methods: Baboons were delivered at 125 d, (term = 185 d) treated with surfactant, and ventilated for 14 d.

Contraceptive action of a gonadotropin-releasing hormone II analog in the rhesus monkey.

GnRH I (mammalian GnRH) was previously thought to be the only isoform of GnRH expressed in mammals, but GnRH II (chicken II GnRH) has now been identified in tissues of numerous mammalian species. Specific high-affinity receptors, which bind GnRH II and its analogs, have been identified throughout the reproductive tract, and GnRH II regulation of progesterone and human chorionic gonadotropin have been demonstrated. Thus, we hypothesized that GnRH II acts as a paracrine factor to regulate extrahypothalamic tissue functions and could be used as an effective contraceptive agent.

Dependence of 3',5'-cyclic adenosine monophosphate--stimulated gonadotropin-releasing hormone release on intracellular calcium levels and L-type calcium channels in superfused GT1-7 neurons.

Objective: Immortalized GT1-7 neurons were used to characterize the interactive roles of adenylate cyclase-3',5'-cyclic adenosine monophosphate (cAMP) and L-type calcium channels on gonadotropin-releasing hormone (GnRH) release.

Methods: Dibutyryl (db)-cAMP was used as an active analog of endogenous cAMP, and forskolin was used to activate adenylate cyclase. Extracellular calcium was chelated using EGTA and L-type calcium channels were blocked using nimodipine.

Treatment of immature baboons for 28 days with early nasal continuous positive airway pressure.

Using the 125-day baboon model of long-term bronchopulmonary dysplasia, we hypothesized that early use of nasal continuous positive airway pressure (nCPAP), a noninvasive ventilatory method, combined with prophylactic surfactant therapy would permit continuation of alveolar and vascular development in the lung. Retrospective human studies have shown that infants treated with nCPAP spend less time on mechanical ventilation and thereby sustain less volutrauma. After delivery by cesarean section at 125 days (term, 185 days), the infants received two doses of surfactant (Curosurf) and daily caffeine citrate.

Distribution of corticotropin releasing hormone in the fetus, newborn, juvenile, and adult baboon.

Corticotropin releasing hormone (CRH) has previously been identified in extrahypothalamic tissues and may act in a paracrine fashion within these tissues. To date, CRH production and its role in the fetus and newborn have not been investigated. The aim of this study was to explore the distribution and ontogeny of CRH in extrahypothalamic tissues of the fetus, newborn, juvenile, and adult baboon.

Action of gonadotropin-releasing hormone II on the baboon ovary.

The content, binding affinity, and bioactivity of chicken II GnRH (GnRH II) and a stable analogue of GnRH II (GnRH II analogue) in the baboon ovary were studied. Although mammalian GnRH is rapidly degraded by baboon ovarian extracts, we designed a GnRH II analogue that is stable to ovarian enzymatic degradation. This analogue binds to the ovarian membranes with high affinity (41 +/- 3 nM), having 20-fold the affinity of a potent mammalian GnRH analogue.

Pregnancy and early reproductive failure in the baboon.

We documented normal pregnancy and the rate of pregnancy failure in female baboons by measuring chorionic gonadotropin (bCG) and progesterone (P) levels in 162 mated cycles of 70 baboon females on days 10, 12, and 14 postovulation. Females were mated with males during turgescene. The presence of pregnancy was defined by bCG levels >20 μg/ml by day 14 postovulation and/or documentation of a gestational sac using ultrasonography.