2006-08-01 07:13:18 · 4 answers · asked by smashbrolover 1 in Science & Mathematics ➔ Biology
Peptide, neuro and steroid hormones. Peptide hormones influence a cells activity by binding to target receptors on the plasma membrane, activation of a second messenger that triggers a response in the cell eg production of enzymes, secretion or permeability. Steroid hormones pass thru the membrane and access the nucleus where the bind to receptor protein where it initiates the expression of specific genes. Neurohormones are released by the hypothalamus' specialised neurones that have both a nervous and secretory role.
2006-08-01 09:51:29 · answer #1 · answered by Allasse 5 · 0⤊ 0⤋
Steroid and Peptide hormones.
2006-08-01 08:31:56 · answer #2 · answered by Stephanie S 6 · 0⤊ 0⤋
One could argue male and female are the 2 "major" classes. Certianly the 2 that the majority of the population is concerned with anyways.
2006-08-01 08:36:52 · answer #3 · answered by pliu428 2 · 0⤊ 0⤋
protein (peptide) hormones, and steroid hormones
2006-08-01 07:36:52 · answer #4 · answered by moose 1 · 0⤊ 0⤋