The effects of substance P on anterior pituitary secretion were studied in 3 female rhesus monkeys. In nine experiments, 100 μg substance P was injected intraventricularly, and the results were compared to those obtained following intraventricular injection of the control vehicle. In 7 out of 9 experiments, substance P induced a significant increase in prolactin secretion within 5 min. Peak levels at 10 min were approximately 15-20 times those of the baseline control. Substance P also induced a slight but significant decrease in GH secretion 20 min following injection, but at other times GH levels were not significantly changed. LH and FSH as well as cortisol concentrations remained unaltered. In 2 monkeys a decrease in systolic pressure of 40–70 mm Hg within 10-60 sec and lasting 180-300 sec was observed following the administration of substance P but not the control vehicle. The results indicate that substance P, which in the monkey has been shown to be associated with hypothalamic regions implicated in the control of anterior pituitary secretion, can alter prolactin and GH release.

We have studied the effects of intra-amniotic administration of an anti-GH-releasing hormone serum (GHRH-Ab) on day 16 of fetal life in the rat, when the ontogenetic development of the GHRH neuronal system occurs. Control animals received normal rabbit serum. Following delivery, body weight was monitored for the next 30 days as an index of somatic growth, and the following indices of somatotrophic function were determined: plasma and pituitary GH, pituitary GH mRNA, hypothalamic GHRH and somatostatin mRNA, and the in vivo GH responsiveness to GHRH. At birth, GHRH-Ab-treated rats had a body weight that was equivalent to that of control rats but, starting from postnatal day 6 up to day 30, they had a significantly reduced body weight. Pituitary weight, the absolute pituitary GH content and GH mRNA levels were lower in experimental compared with control rats, while pituitary GH concentrations were similar in the two groups, thus implying that there was a defect, not only in GH synthesis, but also in GH release. In agreement with this theory, basal GH levels and GHRH-stimulated GH secretion were reduced in GHRH-Ab-treated rats but, in contrast, hypothalamic regulation of GH secretion appeared to be working in these rats as they were still able to respond to the low plasma GH by increasing GHRH and decreasing somatostatin mRNA levels. These findings indicate that deprivation of GHRH during fetal life induces long-lasting changes of growth rate and somatotrophic function.(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of our study was to investigate the effect of hexarelin, a novel GH-releasing peptide-6 analog, and GH-releasing hormone (GHRH) (alone or in combination) on GH secretion in adult patients with increased somatostatin tone due to chronic glucocorticoid excess. We studied seven adult patients undergoing long-term (no less than 6 months) immunosuppressive glucocorticoid treatment for non-endocrine diseases (six females and one male, age range 42-68 years) and one subject (female, age 31 years) with endogenous hypercortisolism due to adrenal adenoma. Six normal subjects (four females and two males) matched for sex and age with the patients and not undergoing any therapy served as controls. All the subjects underwent the following three tests in random order: (1) human GHRH (1-29)NH2 (100 micrograms in 1 ml saline) injected as an i.v. bolus at 0 min, (2) hexarelin (100 micrograms in 1 ml saline) injected as an i.v. bolus at 0 min and (3) hexarelin (100 micrograms in 1 ml of saline) plus GHRH (100 micrograms in 1 ml saline) injected as an i.v. bolus at 0 min. After GHRH alone the patients with glucocorticoid excess showed a blunted GH response as compared with normal subjects (median delta GH: 0.9, range 0-5.6 micrograms/l vs 7:1, range 0.3-14.9 micrograms/l). No significant differences were observed in the steroid-treated group with respect to normal subjects after hexarelin alone (median delta GH: 15.5, range 1.9-45.2 micrograms/l vs 17.9, range 5.5-53.9 micrograms/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Glucocorticoids, when administered over prolonged periods of time, cause protein wasting, osteoporosis, elevation of total cholesterol, and carbohydrate intolerance. Human GH is a potent anabolic agent known to stimulate protein synthesis and osteoblast activity. Chronic hypercortisolemia is associated with impaired GH secretion. The aim of our study was to evaluate the effects of short term administration of human recombinant GH on bone and fuel metabolism in patients receiving chronic glucocorticoid treatment and with suppressed GHRH-stimulated GH peaks (< 10 micrograms/L). We studied nine nonobese adult patients more than 70 yr of age (seven females and two males; age range, 41-68 yr; body mass index, 26 +/- 1.3 kg/m2) undergoing long term glucocorticoid therapy for nonendocrine diseases. After a 3-day stabilization period in the hospital, several parameters were evaluated in all patients: 1) protein, 2) bone, 3) lipid, 4) carbohydrate metabolism, and 5) immune system function under baseline conditions. At 1800 h on the fifth day of hospitalization, the patients began treatment with a daily sc injection of 0.1 IU/kg (0.037 mg/kg) recombinant human GH (Humatrope, Eli Lilly Co.) for 7 days. GH administration caused a significant increase in nitrogen balance (from -0.12 +/- 0.04 to -0.03 +/- 0.02 g/kg.day; P < 0.05), osteocalcin, carboxy-terminal propeptide of type I procollagen, and carboxy-terminal telopeptide of type I collagen with respect to basal levels. After GH administration, total, high density lipoprotein, and low density lipoprotein cholesterol levels were significantly lowered, and serum triglyceride levels were increased in all patients. Normal blood glucose levels during GH administration were observed in our patients concomitantly with a slight increase in insulin secretion. After GH treatment, the T-helper/T-suppressor cell ratio significantly increased with respect to basal levels (2.5 +/- 0.4 vs. 2.2 +/- 0.3; P < 0.05). Our data suggest that in patients receiving chronic glucocorticoid treatment, GH administration may significantly antagonize several side-effects of long term glucocorticoid administration, such as protein wasting, osteoporosis, and hyperlipidemia.

A total of 120 Vibrio species were isolated from 588 patients with acute diarrheal disease during an outbreak of gastrointestinal tract infections at different locations in the lower Cross River Basin of Nigeria. Vibrio cholerae 01, biotype El Tor, serotype Ogawa, was the prominent organism isolated from the Vibrio-associated diarrheal cases. During the 3 months of study, V. cholerae non-Ol was recovered from 10 patients while Vbrio parahaemolyticus was recovered from 19 patients. The significance of this study is the recognition that there is an ecological niche which supports V. cholerae non-Ol and V. parahaemolyticus in the Cross River Basin of Nigeria.