Endocrine and metabolic response to muscarinic stimulation and inhibition in the ruminant: effects of slaframine.

Abstract

The influence of slaframine (SF), a parasympathomimetic compound isolated from the fungus Rizoctonia leguminicola, on circulating metabolic hormone concentrations was investigated in goats. In Exp. 1, SF was administered i.v. at 0 (CONT), 50 (LSF), 100 (MSF), or 150 (HSF) microgram/kg.75 BW in four mature Spanish-cross does (average BW 36 +/- 7 kg) fitted with indwelling jugular vein catheters in a 4 x 4 Latin square design. Plasma glucose peaked (P < .06) at 120 min with LSF and at 180 min with HSF and was higher (P <.06) than the CONT at these times. Glucose exhibited a quadratic response (P < .03) to SF. Area under the response curve for glucose differed (P < .02) in HSF from CONT and MSF. Insulin peaked (P < .01) at 240 min with MSF and at 180 min with HSF. Plasma triiodothyronine was maintained at a higher level (P < .03) with HSF. Thyroxine peaked (P < .06) at 120 min with MSF and 300 min with HSF. Plasma NEFA and somatotropin concentrations were not affected (P > .10) by SF. In Exp. 2, four mature Spanish-cross wethers (average BW 27 +/- 2 kg) fitted with jugular vein catheters were administered SF (0 and 114 micrograms/kg.75 BW) and 4-diphenylacetoxy-N-methylpiperidine methiodide (4DAMP; 0 and 258 micrograms/kg.75 BW), a M3-muscarinic receptor antagonist, i.v. in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. With SF, glucose peaked (P < .06) at 60 min and insulin peaked (P < .05) at 180 min. Plasma triiodothyronine levels were maintained (P < .05) with SF but declined with other treatments. Plasma NEFA and thyroxine concentrations remained unchanged regardless of treatment. Slaframine administration induced hyperglycemia and hyperinsulinemia in goats; however, these changes were blocked by preadministration of isomolar quantities of the M3-muscarinic receptor antagonist, 4DAMP.

• Authors: A M Chapa, J M Fernandez, D L Thompson Jr, R J Tempelman, L F Berrio, W J Croom Jr, W M Hagler Jr
• Journal: Journal of animal science (J Anim Sci) Vol. 73 Issue 12 Pg. 3673-80 (Dec 1995) ISSN: 0021-8812 [Print] United States
• PMID: 8655443 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Alkaloids
• Blood Glucose
• Fatty Acids, Nonesterified
• Insulin
• Muscarinic Agonists
• Muscarinic Antagonists
• Parasympathomimetics
• Piperidines
• Receptors, Muscarinic
• Triiodothyronine
• slaframine
• 4-diphenylacetoxy-1,1-dimethylpiperidinium
• Growth Hormone
• Thyroxine

Topics

• Alkaloids (administration & dosage, pharmacology)
• Animals
• Blood Glucose (analysis)
• Endocrine Glands (drug effects, physiology)
• Fatty Acids, Nonesterified (blood)
• Female
• Goat Diseases (blood, chemically induced)
• Goats (blood, physiology)
• Growth Hormone (blood)
• Hyperglycemia (blood, chemically induced, veterinary)
• Hyperinsulinism (blood, chemically induced, veterinary)
• Injections, Intravenous (veterinary)
• Insulin (blood)
• Male
• Muscarinic Agonists (administration & dosage, pharmacology)
• Muscarinic Antagonists (administration & dosage, pharmacology)
• Parasympathomimetics (administration & dosage, pharmacology)
• Piperidines (administration & dosage, pharmacology)
• Receptors, Muscarinic (drug effects, physiology)
• Thyroxine (blood)
• Triiodothyronine (blood)