Provocation of a paradoxical growth hormone response to corticotropin-releasing hormone by pretreatment with metoclopramide in patients with acromegaly and normal subjects

Two of 7 patients with acromegaly and one of 7 normal subjects exhibited a paradoxical rise in growth hormone (GH) to human corticotropin-releasing hormone (CRH) when pretreated with metoclopramide, although CRH alone did not induce an increase in GH. In one of these two patients with acromegaly, the GH increase to metoclopramide alone also reached the criteria of a paradoxical response. These two acromegalic patients showed a GH increase to metoclopramide pretreatment before and up to two months after surgery. In another acromegalic patient, whose GH level remained high 5 months after surgery, metoclopramide induced an increase in GH level, while in a patient who had an above-normal GH level 18 months after surgery, the resumption of physiological GH secretion after surgery was evidenced by a postoperative absence of a GH response to metoclopramide. It is suggested from these results that the GH response to metoclopramide and the metoclopramide-provoked GH response to CRH in patients with acromegaly result from the secretion of GH from nonadenomatous cells of the pituitary.

Effect of PSK, a protein-bound polysaccharide from Coriolus versicolor, on drug-metabolizing enzymes in sarcoma-180 bearing and normal mice

The effects of PSK and Propionibacterium acnes (anaerobic Corynebacterium) on hepatic drug-metabolizing enzymes were studied using sarcoma-180 bearing and non-tumor bearing mice. PSK had no influence on aminopyrine N-demethylase and aniline hydroxylase activities, cytochrome P-450 concentration in hepatic microsomes, and the reductase activity of cytochrome c in normal mice. The content of cytochrome P-450 was not significantly reduced in S-180 bearing mice. On the other hand, P. acnes administration significantly decreased the amount of cytochromes P-450 and b5 and aminopyrine N-demethylase activity. When FT-207 (Tegafur) was administered orally to S-180 bearing mice combined with the immunoadjuvants, only P. acnes significantly reduced the 5-FU levels in the serum and some organs.

Pituitary-adrenocortical response to metoclopramide in patients with acromegaly and prolactinoma: a clinical evaluation of catecholamine-mediated adrenocorticotropin secretion

We have demonstrated that metoclopramide stimulates cortisol secretion at least in part by a stress-mediated effect in normal men. To examine further the effect of the drug on the hypothalamo-pituitary adrenal system, we studied the cortisol response to 20 mg metoclopramide in patients with acromegaly, prolactinomas, and functional hyperprolactinemia and compared the results with the responses to insulin-induced hypoglycemia. In some patients, the effects of metoclopramide on CRH-induced ACTH and cortisol increase were studied to determine whether a change in dopaminergic (catecholaminergic) activity altered CRH stimulation of pituitary-adrenal function. No cortisol response to 20 mg metoclopramide occurred in 13 tests on 8 of 9 patients with prolactinoma or acromegaly with hyperprolactinemia, whereas both acromegalic patients without hyperprolactinemia had a response. All of the patients had a normal cortisol response to insulin-induced hypoglycemia. Pretreatment with metoclopramide enhanced the CRH-induced cortisol increase from 30-120 min after CRH in normal men, but only at 15 and 30 min in 5 agromegalic patients. The results suggest that metoclopramide acts in the hypothalamus to release ACTH through a dopamine antagonist-mediated (catecholaminergic) mechanism, and that metoclopramide may act additively with CRH to stimulate ACTH secretion in normal men. The absence of a metoclopramide-induced cortisol response in patients with acromegaly or prolactinomas and the absence of a normal cortisol response to metoclopramide-CRH in acromegalic patients could be due to endogenous catecholamine deficiency in these patients.

[Effects of krestin (PSK) on drug-metabolizing enzymes with special reference to the activation of FT-207]

The effects of PSK on hepatic drug-metabolizing enzymes were investigated using Sarcoma 180-bearing and non-tumor-bearing ICR mice. PSK, an immunomodulator, has been commonly used in combination with tegafur for post-operative adjuvant chemotherapy. Tegafur is a typical masked compound transformed into 5-FU by the hepatic drug-metabolizing enzyme P-450. It has been reported that immunostimulants such as BCG and anaerobic Corynebacterium suppress the drug metabolism. PSK and Propionibacterium acnes were administered to mice inoculated s.c. with Sarcoma 180. It was demonstrated that Propionibacterium acnes had an effect of inhibiting these enzymatic activities, especially the amount of P-450 and cytochrome b5 and aminopyrine demethylation. On the other hand, PSK had no influence on the drug-metabolizing enzymes. Propionibacterium acnes was shown to decrease the 5-FU level in organs and sera of mice given FT-207 orally. By contrast, PSK showed no difference in 5-FU level compared to controls, indicating that PSK had no inhibitory effect on the activation of FT-207 by hepatic drug-metabolizing enzymes.