Abstract
Extract: Highly significant (P < 0.0025) increases in adenylate cyclase activity were seen at all fetal age periods (5–17 weeks) whenever sodium fluoride (5–10 mM) was added to the enzyme prepared from human myocardium. Norepinephrine (NE) at 10−4 M significantly elevated adenylate cyclase activity commencing at 6–7 weeks (P < 0.01). Beginning at 8–9 fetal weeks, glucagon (6 × 10−6 M) effectively activated adenylate cyclase. Other hormonal agents, namely, histamine, epinephrine, and isoproterenol at 10−4 M, demonstrated an ability to activate the enzyme (P < 0.025) by as early as 6–7 weeks and continued to act in this manner throughout the remainder of the developmental periods investigated. The α blocker, phentolamine, appeared to have little effect on the enzyme in the presence of NE. The β blocking agent, propranolol, significantly inhibited (P < 0.025) the stimulation of adenylate cyclase by NE throughout the 8–15 fetal week periods.
Speculation: The catalytic (fluoride-sensitive) moiety of adenylate cyclase appears to be present in human fetal myocardium throughout all stages of development. However, the hormonally sensitive receptor components of the enzyme, namely, the catecholamine- and glucagon-sensitive receptors, appear by the 6th-7th and 8th-9th fetal weeks, respectively. Moreover, the catecholamine receptor is most likely of the β type. Likewise, histamine is capable of activating myocardial adenylate cyclase at an early age. Therefore, it appears that at an early period the human fetal heart may have the capability to respond metabolically to sympathetic influences.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Palmer, G., Dail, W. & Scott, H. Appearance of Hormone-sensitive Adenylate Cyclase in the Developing Human Heart. Pediatr Res 9, 98–103 (1975). https://doi.org/10.1203/00006450-197502000-00008
Issue Date:
DOI: https://doi.org/10.1203/00006450-197502000-00008
Keywords
This article is cited by
-
Autonomic responses and neurohumoral control in the human early antenatal heart
Basic Research in Cardiology (1988)
-
Blockade by cimetidine of the effects of histamine on adenylate cyclase activity, spontaneous rate and contractility in the developing praenatal heart
Agents and Actions (1979)