Chapter 3 — Further Reading

Tier 1 — Verified canonical

Endocrine physiology. Guyton and Hall's Textbook of Medical Physiology is the standard reference for the axes, feedback control, and the pancreatic islet. Its endocrine chapters are considerably more readable than their reputation suggests and cover everything in this chapter at greater depth. Williams Textbook of Endocrinology is the specialist reference if you want the clinical detail — including diagnostic testing, which is where pulsatility stops being an abstraction and becomes a practical problem.

Bayliss and Starling, 1902. The secretin experiment was published in the Journal of Physiology and is one of the most consequential papers in the history of physiology. Starling coined the word "hormone" shortly afterward, in his Croonian Lectures. Both are old enough to be freely available through public archives, and the 1902 paper is short and remarkably readable — worth thirty minutes if you have never read a primary source from this era.

Claude Bernard and the concept of the milieu intérieur — the internal environment maintained constant despite external change — is the intellectual ancestor of homeostasis. Walter Cannon coined "homeostasis" itself in the 1920s and popularized it in The Wisdom of the Body (1932), which remains readable.

Cadaver-derived growth hormone and Creutzfeldt-Jakob disease. This is well documented in the public health literature. The U.S. National Institute of Diabetes and Digestive and Kidney Diseases maintained a long-running follow-up study of recipients of the National Hormone and Pituitary Program, and the CDC publishes material on iatrogenic Creutzfeldt-Jakob disease. Both are free and authoritative. The distribution halt occurred in 1985.

The 1997 Nobel Prize in Physiology or Medicine was awarded to Stanley B. Prusiner for the discovery of prions — the mechanism that made the cadaver hormone tragedy possible and that was not understood when those purification processes were designed. The lecture is free.

Recombinant human insulin was approved in 1982, the first recombinant drug; recombinant human growth hormone followed in the mid-1980s. FDA approval records are public via Drugs@FDA.

Tier 2 — Attributed, specifics unverified

On pulse frequency encoding. That GnRH pulse frequency differentially favors LH versus FSH release is well established in reproductive endocrinology, and the therapeutic exploitation of continuous versus pulsatile GnRH delivery is standard clinical practice. Precise frequency figures vary by species, sex, and reproductive stage; this book gives the human interpulse interval as "roughly every 60 to 90 minutes," which is the commonly cited range.

On growth hormone pulse patterns. That GH secretion is strongly pulsatile with the largest bursts during slow-wave sleep is standard endocrinology. Precise pulse amplitudes and frequencies vary with age, sex, body composition, and sleep quality, which is exactly why random single measurements are uninterpretable and why IGF-1 or stimulation testing is used instead.

On the number of pituitaries required per patient-year of cadaver growth hormone. Reported figures vary considerably across sources and programs. This book states the constraint qualitatively — that supply was the permanent binding limitation and required rationing — rather than giving a specific ratio, deliberately.

On the Pavlov laboratory coda in Case Study 1. The account that a researcher in Pavlov's laboratory came close to the secretin result and did not pursue it is widely repeated in histories of endocrinology. The precise historical record of who observed what and when is not fully settled, and the case study labels it as characterization rather than established fact. The general pattern it illustrates — anomalies inside successful frameworks being attributed to error — is very well documented independently.

On the completeness of the endocrine organ list. That fat, muscle, bone, gut, heart, and kidney all perform endocrine functions is well established; the list continues to grow, and any statement that a given organ "is not endocrine" should be treated as provisional.

Tier 3 — Illustrative and constructed

• All ASCII diagrams in this chapter — the three-tier structure, the four axes, the feedback comparison, the pulsatile-versus-continuous plot, and the glucose control loop — are schematic teaching devices, not to scale.
• The worked Field 2 dossier entries for growth hormone and CJC-1295 are demonstrations constructed for this book from publicly available information.
• The axis-reading table in §3.9 is this book's own summary device; the individual drug facts in it are Tier 1 and are developed in the chapters cited.

If you only read one thing

The Bayliss and Starling 1902 paper.

It is short, it is free, and it does something modern papers almost never do: you can follow the entire logical structure of a field-creating experiment in a few pages, including the part where they cut the nerves and the effect stubbornly persisted.

It is also a useful calibration exercise. Read it and ask what it would take to publish that result today — how many more controls, how many more animals, how much more statistical machinery. Then ask whether the conclusion would be any more secure. There is a real argument on both sides, and holding it will make you a better reader of Chapter 5.

Looking ahead

Chapter 4 covers pharmacokinetics — absorption, distribution, metabolism, clearance, and half-life. The useful background is the concept of bioavailability, and Goodman & Gilman covers it thoroughly. If you would rather have one specific thing to look at, find the label for oral semaglutide (Rybelsus) on DailyMed and read its administration instructions. The fasting window and the water volume specified are pharmacokinetics made visible, and Chapter 4 explains every line of it.