Growth Hormone: Metabolic Clearance Rates, Integrated Concentrations, and Production Rates in Normal Adults and the Effect of Prednisone

Abstract

A B S T R A C T A constant withdrawal pump was used to determine the integrated concentration of growth hormone (ICGH) which was used in conjunction with the metabolic clearance rate (MCR) of growth hormone (GH) to calculate the GH production rates (GHPR) in normal adults, acromegalics, and normal controls receiving prednisone.The mean ICGH for 22 premenopausal females on no medication was 3.0±1.6 ng/ml (SD) which is significantly lower (P < 0.005) than the mean of 6.6±2.9 for 10 women receiving oral contraceptives and significantly higher than the means of 1.5±0.75 for 5 postmenopausal females (P < 0.05) and 1.8±1.0 for 16 adult males (P < 0.01) which are comparable. The mean GHPR's in mg/24 hr per m' for the four groups are: normal females 0.52±0.24 (SD), females receiving contraceptive pills 1.65±0.58 (P < 0.005), postmenopausal females = 0.26±0.12 (P < 0.025), and adult males 0.35±0.23 (P < 0.025).Three untreated acromegalic patients had ICGH's of 59, 82, and 93 ng/ml and GHPR's ranging from 14.5 to 17.9 mg/24 hr.Prednisone in a dose of 20 mg t.i.d. for 8 days significantly decreased both the ICGH and GHPR. Alternate day prednisone (60 mg in a single q.o.d. dose) resulted in less consistent inhibition of GH -release which may play a role in the more normal growth seen in children receiving q.o.d. prednisone.

Endocrine dysfunction and parameters of the metabolic syndrome after bone marrow transplantation during childhood and adolescence

“…22 We found a significant association between GH deficiency and corticosteroid therapy, administered as part of the treatment protocol of the underlying disease, although the GH deficiency was diagnosed at least 3 years after corticosteroids were discontinued. Many studies have reported a significant incidence of GH deficiency following cranial irradiation, 19,23 and also after TBI.…”

“…Three patients (3.3%) were diagnosed with type II diabetes mellitus and three (3.3%) with IGT at a mean age of 21.576.1 years (range, [15][16][17][18][19][20][21][22][23][24][25][26][27][28]. A BMI-SDS of o2 was noted in all three patients with diabetes and in two of the three patients with IGT.…”

Metabolic clearance and production rates of prolactin in man.

“…Saturation of PRL metabolic pathways by high hormone concentrations is one possible mechanism that would explain our findings. Although GH MCR in acromegalic patients was found to be no different from normal by two groups (2, 4), it was lower than controls in three patients studied by Thompson et al (5). A recent study in the rat demonstrated that in vivo binding of 125I1 GH to putative hepatic GH receptors was decreased by simultaneous administration of unlabeled GH (36).…”

“…The MCR of growth hormone (GH), luteinizing hormone, follicle-stimulating hormone, thyrotropinstimulating hormone (TSH), and the subunits of TSH have been determined by this method (2)(3)(4)(5)(6)(7)(8)(9). Although the MCR of prolactini (PRL) has been imeasured in both the rat (10) ani-d sheep (11) in this mannier, comparable data in humanis have not been reported.…”

Enhanced basal and disorderly growth hormone secretion distinguish acromegalic from normal pulsatile growth hormone release.

“…However, little is known about the nature of the secretory events at the level of the anterior pituitary gland that give rise to these changes in serum GH concentrations. Secretion cannot be inferred readily from the serum GH concentrations, because of the confounding influence of ongoing metabolic clearance, which has been reported to be normal (3)(4)(5)(6), increased (7,8) or decreased (6,9,10) in acromegaly. Furthermore, whether episodes of GH secretion arise from normal hypothalamic regulation or from random events intrinsic to adenomatous tissue is unknown.…”